> Am 15.11.2018 um 16:47 schrieb Will Deacon <will.deacon@xxxxxxx>: > >> On Tue, Nov 13, 2018 at 04:29:06PM +0100, Alexander Graf wrote: >> I've already stumbled over 2 cases where people got confused about how to >> disable kpti on AArch64. In both cases, they used existing x86_64 options >> and just applied that to an AArch64 system, expecting it to work. >> >> I think it makes a lot of sense to have compatible kernel command line >> parameters whenever we can have them be compatible. >> >> So this patch adds the pti= and no_pti kernel command line options, mapping >> them into the existing kpti= command line framework. It preserves the old >> syntax to maintain compatibility with older command lines. >> >> While at it, the patch also marks the respective options as dual-arch. >> >> Reported-by: Richard Brown <rbrown@xxxxxxx> >> Signed-off-by: Alexander Graf <agraf@xxxxxxx> >> >> --- >> >> v1 -> v2: >> >> - Actually make it compile. Sorry for the sloppy v1. >> --- >> Documentation/admin-guide/kernel-parameters.txt | 6 +++--- >> arch/arm64/kernel/cpufeature.c | 20 +++++++++++++++++++- >> 2 files changed, 22 insertions(+), 4 deletions(-) > > This patch doesn't help though, right, because kpti= has already been > included with backports etc so the ship has sailed? Not necessarily. We can always mark this as stable and have distros pull it in. Consistency is definitely useful for everyone. > Yeah, it's not ideal, > but we went over this before: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2018-August/598395.html Ah, I mist havd missed that. But if you already have 2 people sending very similar patches, there is probably something to it :). > > The thing we really need is the sysfs interface hooking up so you can easily > check the state of the mitigation. Still waiting for a follow-up on that ;) > > http://lists.infradead.org/pipermail/linux-arm-kernel/2018-September/603412.html That one is very much needed as well, yes. Alex > > Will
